How to Bring Alkalinity Down in a Hot Tub

Like if this guide is helpful
How to Bring Alkalinity Down in a Hot Tub

Relaxing in a backyard hot tub is a great way to unwind. Despite the fact that hot tubs are much smaller than swimming pools, they still require consistent maintenance, particularly for the water. Because hot tubs remain at a consistently high temperature, they can be breeding grounds for bacteria if not properly maintained. Bringing the alkalinity down in a hot tub is one simple way of ensuring that the spa lasts for years and does not cause skin irritation or infection.


Know the Signs of High Alkalinity

Before attempting to lower the total alkalinity of a hot tub, it is important to know the signs of high alkalinity. Every hot tub is different, but some of the most common signs of this problem include:

  • Scales forming
  • Cloudy water
  • Skin irritation
  • Eye irritation
  • Sanitizer inefficiency

None or all of these symptoms may be present in any spa with high alkalinity. If at least one is present, testing the alkalinity is a good place to start.


Total Alkalinity vs. pH

When dealing with water in a spa, it can be difficult to understand the difference between total alkalinity, sometimes abbreviated as TA, and pH. The pH of the water is a measurement of how much acid is in the water. A lower pH means less acid, while a higher pH measurement means more acid is present. On the other hand, total alkalinity is the ability of the water to reach equilibrium between acidic and basic element. When the TA is off, it is impossible to bring the pH into balance.


Test the Water

Hot tub test strips are widely available. Be sure to test both the total alkalinity and the pH levels in the spa before proceeding. The strips or spa testing kit should distinguish the approximate alkalinity of the water in parts per million (PPM). If the total alkalinity is higher than 120 PPM, then it is time to lower it.


Instructions for Lowering Alkalinity

The main way to lower the total alkalinity of a hot tub is to use a chemical specifically designed for the purpose. These chemical agents generally use either muriatic acid or dry sodium bisulfate to lower the spa's alkalinity. There are many different brands available, depending on both the volume and price desired.

Add the Appropriate Chemical

Using the total volume of the hot tub, determine how much chemical is necessary, and measure out that amount. Generally, 1.6 pounds of sodium bisulfate or 1.3 quarts of muriatic acid is enough to lower the alkalinity of a 10,000-gallon hot tub by 10 PPM, but be sure to follow the manufacturer's instructions when adding the chemical. Usually, it is necessary to dilute the chemical in a small amount of water before adding it to the hot tub, which allows for more even distribution. Pour the chemical into the center of the hot tub slowly. For safety purposes, no one should be in the hot tub during this process.

Aerate the Water

Lowering the total alkalinity of the water in a hot tub also lowers the total pH. To prevent the pH from getting too low, aerate the water. The easiest way to add air to the water is to run the hot tub's jets. This aeration can also help to thoroughly mix the chemicals into the water and lower the alkalinity more effectively.

Test the Water Again

After allowing the water in the hot tub to circulate for at least three hours, test the alkalinity levels once again with a test strip or alkalinity testing kit. The levels should be between 80 and 120 PPM for best operation. If the TA is still too high after the first attempt, add more of the chemical solution per the manufacturer's instructions.


How to Buy a Hot Tub on eBay

Whether you are in the market for a new hot tub or you just need the right chemicals to keep yours running efficiently, eBay is a great place to shop. Use the search box located on any page to type words and phrases that describe what you need, whether that is "Spa Down" or "Hot Tub Bromine." If you get too many results, you can always use filters to narrow the list by brand, price, seller location, and more.

Explore more guides